The invention relates in general to methods and apparatus for operator interfacing with electrical devices, and more particularly to a pneumatic switch interface which allows physically disabled people to interact with a computer.
Even the most routine tasks most people encounter in everyday life, including operating televisions, telephones, computers and other electronic equipment, become great challenges when attempted by a severely physically handicapped person. As a result, physically disabled persons are largely forced to be dependent on others to help them accomplish these basic needs.
Previously, substantial efforts have been devoted to the design of user-operated devices that permit the physically disabled to perform tasks by exploiting the abilities they do have. Thus, a number of devices have been developed which are adapted to be operated by extremities in which even severely physically handicapped people typically retain some degree of movement. One such device is disclosed in U.S. Pat. No. 3,229,059 to Beatty, which comprises a chin-operated switching controller that controls a television or radio when a person turns his head from side-to-side.
Although devices such as the Beatty controller allow handicapped persons to perform simple tasks, they are becoming increasingly disfavored due to their limited capability. Another approach is to use breath-controlled switches, which are especially helpful for the more severely physically handicapped persons, such as quadriplegics or bed-ridden patients. U.S. Pat. No. 4,298,863 to Natitus et al. discloses such a device wherein a bed-ridden patient blows on the pneumatic transducer of a portable patient call system to produce an alarm signal for calling a nurse. U.S. Pat. Nos. 3,848,249 to Meiri and 4,453,043 to Zielinski et al. disclose controllers for persons with motor impairments which automatically dial a telephone number when a person blows on a breath-operated microswitch. U.S. Pat. No. 4,207,959 to Youdin et al. discloses a voice-activated wheelchair controller with a plurality of breath-control tubes which override speech-activated control circuits to manually operate the movement of a motorized wheelchair. These devices help severely physically handicapped persons to perform various very simple tasks, but none are sophisticated enough to enable physically handicapped persons perform the complex tasks involved in operating a computer.
One computer input device that allows a physically impaired person to perform a limited number of functions on a computer is described in U.S. Pat. No. 4,567,479 to Boyd. The Boyd device comprises vacuum-operated switches which are controlled by a separate breath-control tube. Each switch generates when actuated a control signal that is connected directly into a computer which is controlled by a specially-modified software program. The control signal generated by each switch is associated with a different single operation to be performed by the computer as specified by the modified program. The Boyd input device is thus not adaptable to other computers or computer programs without creating new interface software and hardware specific to each computer and computer program. In addition, the Boyd input device is cranially mounted and operated, which may easily fatigue a physically disabled user after prolonged use. Further, because the Boyd input device is cranially operated, a user may require assistance from another when placing or removing such a device from his or her head.